Electromagnetic sensors in the frequency range used for radar and communications are affected by refractive effects of the atmosphere. The irregularities in the refractive conditions are caused by rapidly changing gradients of water vapor contents and air temperature. Observing refractive conditions, and taking due, application specific, actions may improve the performance of the system.

Refraction irregularities are common in marine environment especially close to shore in various weather conditions, when different air masses, dry and humid, are not mixed well enough, and when the evaporation from the sea surface causes sharp changes to the vertical profile of the water vapor contents.

The operators of radar and communication systems can measure the needed atmospheric parameters using observing system comprising a number of different sensors. In addition to the conventional radiosondes and surface measurements systems the new low altitude rocketsonde and floatsonde technology is available.

The low level rocketsonde, dropsonde payload released in the apogee of the rocket, measures the temperature and relative humidity profile from about 1 km altitude down to the sea surface. The floatsonde complements the profile with sea surface temperature and very low level air temperature measurements.